Recently, it is expected to realize a high speed, less expensive, and small optical transceiver which is used in optical communications represented by local area networks, metropolitan area networks, and the like as well as used in optical links in and between servers and routers. The optical transceiver is composed of a light transmitting portion and a light receiving portion, in which a module of the light transmitting portion has a transmitting LSI and a light emitting device such as a semiconductor laser and the like, and a module of the light receiving portion has a receiving LSI and a light receiving device such as a photodiode.
Heretofore, in this type of optoelectronic hybrid integrated modules, a light coupling system is formed by mounting an optical device on a substrate on which an optical waveguide is formed and coupling it with the optical waveguide, and light is input from and output to the outside by coupling an end of the optical waveguide with an optical fiber. Further, to compose input/output fibers of a single fiber, an access network employs a structure for discriminating the signal wavelengths of a light emitting device and a light receiving device and sorting the wavelengths by inserting an optical filter in a midway. Then, in a transmission/reception integral type optical module, since it is necessary to suppress stray light and electromagnetic wave noise, various reduction means are conventionally employed. For example, a conventional light transmitting module disclosed in Japanese Patent Application Laid-Open No. 2001-249241 (pages 3-4, FIGS. 1 and 2) employs such a structure that a light shield plate having a hole is inserted into an optical waveguide between a light emitting device and a light receiving device so that light passes in the vicinity of the light emitting device and is shielded on the outside of it to thereby suppress stray light which is not coupled with the optical waveguide from the light emitting device.
Further, as another structure capable of suppressing stray light, Japanese Patent Application Laid-Open No. 2001-174675 (page 3, FIGS. 1 and 2), for example, proposes a structure arranged such that the peripheries of a light emitting device and a light receiving device are covered with a transparent resin in a dome state, and the outsides of them are coated with light shield resin covering portions. According to the structure, stray light can be prevented from being leaked to the outside as well as the light from the outside is prevented from being received by the light receiving device.
In contrast, as a structure for suppressing electromagnetic wave noise, there are employed a countermeasure of increasing a distance between a transmitting portion and a receiving portion to prevent electromagnetic wave noise caused by driving a light emitting device from reaching a receiving side and being amplified by a receiving LSI, and a countermeasure of covering an overall substrate, on which a device of a receiving portion, for example, is mounted, with an electromagnetic wave shielding module package.